Dental Hypotheses

ORIGINAL HYPOTHESIS
Year
: 2015  |  Volume : 6  |  Issue : 3  |  Page : 94--96

Functional treatment of skeletal Class II malocclusion using bone-anchored devices and intermaxillary elastics


Mahmood Reza Kalantar Motamedi1, Alimohammad Kalantar Motamedi2,  
1 Department of Research, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan, Iran
2 Department of Orthodontics, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan, Iran

Correspondence Address:
Alimohammad Kalantar Motamedi
Department of Orthodontics, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan
Iran

Abstract

Introduction: Dentofacial functional appliances used for the treatment of skeletal Class II malocclusion are divided into two groups: Removable appliances and fixed (bonded) appliances, each with certain advantages and disadvantages. Considering the problems related to functional appliances such as high volume in the oral cavity, patient noncompliance, esthetics, tissue irritation or ulceration, speech or breathing difficulties, etc., there is considerable demand to develop a new appliance that can overcome these issues. Thus, the aim of the current study is to present a hypothesis regarding a new functional treatment technique. The hypothesis: We hypothesize that by fixing mini-plates or -implants in the posterior region of the mandible and the anterior part of the infrazygomatic crest region of the maxilla using intermaxillary elastics, we can expect a forward growth of the mandible in a growing child. Using this technique, the force vector will be in the oblique (forward-upward) direction. By installing mini-plates with a long connecting bar in the infrazygomatic crest region (with the orthodontic attachment head approximating the level of the occlusal plane), and mini-plates or -implants in the most posterior and superior regions of the mandible, such as the retromolar region, the force vector can be placed in the most horizontal direction possible. Evaluation of the hypothesis: In the literature, significant growth modification results were reported in skeletal Class III patients using intermaxillary elastics and bone-anchored devices fixed in both jaws, when compared with those in the nontreatment group. Therefore, in practice, intermaxillary elastics can produce enough traction to stimulate the bone to change and grow. Thus, we presume that inverting the direction of the force vector (i.e., posterior-anterior force) may have similar growth effects on the mandibles of growing children.



How to cite this article:
Motamedi MR, Motamedi AK. Functional treatment of skeletal Class II malocclusion using bone-anchored devices and intermaxillary elastics.Dent Hypotheses 2015;6:94-96


How to cite this URL:
Motamedi MR, Motamedi AK. Functional treatment of skeletal Class II malocclusion using bone-anchored devices and intermaxillary elastics. Dent Hypotheses [serial online] 2015 [cited 2021 May 7 ];6:94-96
Available from: http://www.dentalhypotheses.com/text.asp?2015/6/3/94/163812


Full Text

 Introduction



The influences of natural forces and functional stimuli on form were first reported by Roux (1883) as a result of his surveys on the tail fins of dolphins. In fact, his working hypothesis became the biomechanical background of general orthopedics and functional jaw orthopedics. [1]

It is believed that functional appliances are the first orthopedic implements influencing the facial skeleton of a growing child in the condylar and structural areas, leading to skeletal improvement. They are used in various situations, including external movement of the condyle from the fossa, alleviation of pressure on condylar tissues, and alterations in muscular strain.

Dentofacial functional appliances used for the treatment of skeletal Class II malocclusion are divided into two groups: Removable appliances (such as Mono-block, Twin-block, and Frankel functional appliance) and fixed (bonded) appliances [such as Herbst and mandibular anterior repositioning appliance (MARA)], each with certain advantages and disadvantages. The drawbacks of removable functional appliances include high volume in the oral cavity, patient noncompliance, esthetics, tissue irritation or ulceration, and speech or breathing difficulties. The highest bone growth and active teeth eruption have been reported to occur during the night (between 8 PM and 1 AM), when the secretion of growth hormone is at its peak. [2],[3] Therefore, the child is advised to use the functional appliance during this period (after dinner until the next morning), for a total period of about 12 h. Although continuous use of the appliance during the day can also be beneficial to the child, factors such as interference with school time and breaking or loss of the appliance must be considered.

Fixed functional appliances cause undesirable tooth movements due to their inherent continuous force application as compared with removable functional appliances. [4] The other drawbacks of these appliances include eating difficulties, restricted jaw movements, and probable device fractures. More importantly, these tools can lead to intrusion of the posterior teeth in the maxilla. [5],[6] In general, nearly all of the functional appliances, whether removable or bonded, lead to proclination of the mandibular incisors.

Considering the problems related to functional appliances for the correction of skeletal Class II malocclusion, there is considerable demand to develop a new appliance that can overcome these issues. Thus, the aim of the current study is to present a hypothesis regarding a new functional treatment technique.

 The Hypothesis



We hypothesize that by fixing mini-plates or -implants in the posterior region of the mandible and the anterior part of the infrazygomatic crest region of the maxilla using intermaxillary elastics, we can expect a forward growth of the mandible in a growing child. Using this technique, the force vector will be in the oblique (forward-upward) direction. By installing mini-plates with a long connecting bar in the infrazygomatic crest region (with the orthodontic attachment head approximating the level of the occlusal plane), and mini-plates or -implants in the most posterior and superior regions of the mandible, such as the retromolar region, [7] the force vector can be placed at the most horizontal direction possible. This direction is important for the achievement of the most forward growth of the mandible possible. Therefore, by managing the placement of the skeletal anchorage devices, we can manipulate the direction of growth according to factors such as the vertical growth pattern of the patient's jaws. These factors are not always manageable when using traditional functional appliances.

 Evaluation of the hypothesis



The proposed hypothesis can be evaluated subjectively and objectively; it is clear that there is a strain and forward force in the mandible when using Class II elastics attached to the upper and lower dentitions in patients with dental Class II malocclusion. This strain can lead to growth modifications in a growing child. Elsewhere in the literature, significant results were reported in skeletal Class III patients using intermaxillary elastics and bone-anchored devices fixed in both jaws, when compared with those in the nontreatment group. [8] Similar results have been reported by the same author in a previous study, [9] wherein an anterior-posterior force was used for the correction of the malocclusion. Therefore, in practice, intermaxillary elastics can produce enough traction to stimulate the bone to change and grow. Thus, we presume that inverting the direction of the force vector (i.e., posterior-anterior force) may have similar growth effects on the mandibles of growing children. In this situation, maximal anchorage is achieved without any dental movement. A study that three-dimensionally analyzed maxillary protraction with intermaxillary elastics and mini-plates for the treatment of skeletal Class III patients showed maxillary advancement with little effect on the dentoalveolar units. [10] Another important advantage of this device is that it can be used continuously without the difficulties, mentioned above, of a fixed or removable appliance, thereby expediting desirable outcomes.

Limitations of the hypothesis

Most of the children who need functional therapy are in the mixed dentition period, and therefore using mini-plates or -implants may cause damage to the tooth buds. However, nowadays, by using computerized radiography it can be obviated and surgeons can exactly insert the implants at the right desired point. Moreover, installing a mini-plate or -implant in the most posterior and superior regions of the mandible does not interfere with any tooth bud at the mixed dentition age. Inserting a mini-implant in the infrazygomatic region can be somewhat dangerous; however, by installing a mini-plate with a long connecting bar on the infrazygomatic crest region, we can overcome the danger [Figure 1]. The schematic shown in [Figure 1] is inspired from the study of Cha et al., where a cantilever-type surgical mini-plate was fixed in the infrazygomatic crest and then its end was modified as a hook. [11] {Figure 1}

On the other hand, in the late childhood period close to the growth spurt, continuous use of the appliance during the day is needed to achieve the growth outcomes of interest, but most of the children are not compliant with nonesthetic and uncomfortable traditional functional appliances. At this point, the hypothesized technique can be the key solution because the class II elastics are more compliant and esthetic.

 Conclusion



In conclusion, combined functional therapy using intermaxillary elastics and skeletal anchorage devices in the upper and lower jaws might be considered as a novel, simple, and beneficial technique for the treatment of skeletal Class II malocclusion in growing children. However, such a claim can only be proved by the conduction of clinical studies in future.

Financial support and sponsorship

The authors do not have any financial support.

Conflicts of interest

There are no conflicts of interest.

References

1Roux W. Gesammelte Abhandlungen über Entwickelungsmechanik der Organismen: Leipzig : Wilhelm Engelmann. Available form: https://archive.org/details/gesammelteabhand01roux. 1895.
2Stevenson S, Hunziker EB, Herrmann W, Schenk RK. Is longitudinal bone growth influenced by diurnal variation in the mitotic activity of chondrocytes of the growth plate? J Orthop Res 1990;8:132-5.
3Risinger RK, Proffit WR. Continuous overnight observation of human premolar eruption. Arch Oral Biol 1996;41:779-89.
4Pancherz H, Malmgren O, Hägg U, Omblus J, Hansen K. Class II correction in Herbst and Bass therapy. Eur J Orthod 1989;11:17-30.
5Pancherz H. The effects, limitations, and long-termdentofacial adaptations to treatment with the herbst appliance. Semin Orthod 1997;3:232-43.
6Lund DI, Sandler PJ. The effects of twin blocks: A prospective controlled study. Am J Orthod Dentofacial Orthop 1998;113:104-10.
7Cornelis MA, De Clerck HJ. Biomechanics of skeletal anchorage. Part 1. Class II extraction treatment. J Clin Orthod 2006;40:261-9; quiz 32.
8De Clerck H, Cevidanes L, Baccetti T. Dentofacial effects of bone-anchored maxillary protraction: A controlled study of consecutively treated Class III patients. Am J Orthod Dentofacial Orthop 2010;138:577-81.
9De Clerck HJ, Cornelis MA, Cevidanes LH, Heymann GC, Tulloch CJ. Orthopedic traction of the maxilla with miniplates: A new perspective for treatment of midface deficiency. J Oral Maxillofac Surg 2009;67:2123-9.
10Heymann GC, Cevidanes L, Cornelis M, De Clerck HJ, Tulloch JF. Three-dimensional analysis of maxillary protraction with intermaxillary elastics to miniplates. Am J Orthod Dentofacial Orthop 2010;137:274-84.
11Cha BK, Choi DS, Jang I, Jost-Brinkman PG, Ngan P. Maxillary protraction using miniplates as skeletal anchorage. Hong Kong Dent J 2010;7:87-93.